The color of rockets，shells，or rocket parachute flares used to indicate that the vessel is in distress and requires immediate assistance is（）.

A.on or near the navigating bridge
B.on the flying bridge not closer than 15 feet to any bulkhead
C.above the freeboard deck away from heat
D.in an enclosed space below the freeboard deck away from heat

A.sea state
B.names of witnesses
C.time of its occurrence
D.wind direction and velocity

A.the gun is being used to sound passing signals
B.the vessel is in distress
C.all vessels are to clear the area
D.all is clear and it is safe to pass